[SLOF] [PATCH slof v2] fdt: Pass the resulting device tree to QEMU

[Greg Kurz]

On Mon,  2 Oct 2017 16:38:19 +1100
Alexey Kardashevskiy <aik at ozlabs.ru> wrote:

> This creates flatten device tree and passes it to QEMU via a custom
> hypercall right before jumping to RTAS.
> 
> On a machine with 256 CPUs and 256 virtual Intel E1000 devices the blob
> is 360KB (356KB structs and 20KB of strings), building such a tree takes
> ~2s on a POWER8 box. A simple tree with 1 CPU and a couple of devices
> takes 38ms and creates 16KB blob.
> 
> This preloads strings with 40 property names from CPU and PCI device nodes
> and the strings lookup only searches within these. Without string reusing
> at all, the strings blob is 200KB and rendering time is 1.7sec; with
> unlimited reusing, the strings blob is 4KB and rendering time is 2.8sec.
> 
> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
> ---
> 
> Changes:
> v2:
> * fixed comments from review
> * added strings cache
> * changed last_compat_vers from 0x17 to 0x16 as suggested by dwg
> 

I wanted to give a try with PHB hotplug and SLOF breaks, because...

[...]
> diff --git a/board-qemu/slof/rtas.fs b/board-qemu/slof/rtas.fs
> index 54d3929..5beb079 100644
> --- a/board-qemu/slof/rtas.fs
> +++ b/board-qemu/slof/rtas.fs
> @@ -98,6 +98,10 @@ find-qemu-rtas
>  ;
>  
>  : rtas-quiesce ( -- )
> +    " /" find-node
> +    fdt-flatten-tree
> +    dup hv-update-dt

.. this leaves the hcall return value on the stack. Maybe add:

   ?dup IF
      \ Ignore hcall not implemented error, print error otherwise
      dup -2 <> IF ." HV-UPDATE-DT error: " . cr ELSE drop THEN
   THEN

> +    fdt-flatten-tree-free
>      " quiesce" rtas-get-token rtas-cb rtas>token l!
>      0 rtas-cb rtas>nargs l!
>      0 rtas-cb rtas>nret l!
> diff --git a/lib/libhvcall/hvcall.code b/lib/libhvcall/hvcall.code
> index 8349748..6ff5715 100644
> --- a/lib/libhvcall/hvcall.code
> +++ b/lib/libhvcall/hvcall.code
> @@ -136,3 +136,8 @@ PRIM(hv_X2d_update_X2d_phandle)
>  	uint32_t old_phandle = TOS.u;
>  	TOS.u = hv_generic(KVMPPC_H_UPDATE_PHANDLE, old_phandle, new_phandle);
>  MIRP
> +
> +PRIM(hv_X2d_update_X2d_dt)
> +	unsigned long dt = TOS.u;
> +	TOS.u = hv_generic(KVMPPC_H_UPDATE_DT, dt);
> +MIRP
> diff --git a/lib/libhvcall/hvcall.in b/lib/libhvcall/hvcall.in
> index ab7513a..b59e3f7 100644
> --- a/lib/libhvcall/hvcall.in
> +++ b/lib/libhvcall/hvcall.in
> @@ -32,4 +32,5 @@ cod(hv-logical-memop)
>  cod(hv-cas)
>  cod(hv-rtas-update)
>  cod(hv-update-phandle)
> +cod(hv-update-dt)
>  cod(get-print-version)